Variables and Constants in C Programming

 INTRODUCTION:-

In C programming, variables and constants are used to store data.

They are fundamental concepts that every beginner must understand before writing complex programs.

What is a Variable?

~A variable is a name given to a memory location used to store data.

The value of a variable can change during program execution.

Syntax:

data_type variable_name;

Example:

int age = 18;

float salary = 25000.5;

In this example:

  • age is a variable of type int
  • salary is a variable of type float

Rules for Naming Variables:-

  • Must start with a letter or underscore
  • Cannot start with a number
  • Cannot use C keywords
  • Case-sensitive (Age and age are different)

What is a Constant?

~A constant is a value that cannot be changed during program execution.

Example:

const int year = 2025;

**Here, the value of year cannot be modified.**

Types of Constants in C:-

  1. Integer constants (10, 100, -5)
  2. Floating constants (3.14, 2.5)
  3. Character constants ('A', 'b')
  4. String constants ("Hello")

Difference Between Variable and Constant

Variable : Constant

Value can change : Value cannot change

Uses memory location : Fixed value

Declared normally : Declared using const

Conclusion:-

Variables and constants are the building blocks of every C program.

Understanding them clearly will make learning operators and expressions much easier.

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